<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>What you can do with the library</title><link rel="stylesheet" type="text/css" href="manual.css"><meta name="generator" content="DocBook XSL Stylesheets V1.76.0"><link rel="home" href="index.html" title="JpGraph Manual"><link rel="up" href="ch01.html" title="Chapter 1. About the library"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">What you can do with the library</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center">Chapter 1. About the library</th><td width="20%" align="right"> </td></tr></table><hr></div><div class="sect1" title="What you can do with the library"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2472677"></a>What you can do with the library</h2></div></div></div>
            
            <p>One should probably differentiate between the two basic usage scenarios</p>
            <p>
                </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
                        <p><span class="bold"><strong>Online.</strong></span> That is, the image is dynamically
                            generated when a user is viewing a particular WEB-page. This means that
                            the time it takes to generate the image will add to the delay the user
                            is experiencing when trying to view the page. (The library supports a
                            caching mechanism to reduce the number of times an image has to
                            generated, see <a class="xref" href="ch05s06.html" title="Efficient graph generation using the built-in cache subsystem">Efficient graph generation using the built-in cache subsystem</a> for a thorough
                            discussion). For this scenario one should probably keep the images as
                            basic as possible in order to have as small latency as possible. </p>
                        <p>In practice this means that the number of data points to visualize
                            should be kept in the order of hundreds and not thousands. In later
                            sections we will discuss in details what can be done to improve the
                            performance of the library.</p>
                        <p> </p>
                    </li><li class="listitem">
                        <p><span class="bold"><strong>Offline</strong></span>. That is, the images are generated by
                            some "batch" processing (possible command line based). In this scenario
                            the delay is not an issue and one could create much more complicated
                            images and process many more data points. Even though the library in
                            itself does not impose any restriction of the number of data points to
                            process the memory and time limits set for PHP will. </p>
                        <p>In practice if you need to process images with sizes above 2000x2000
                            pixels resulting from processing 500,000 data points then it is probably
                            better to find a more suitable way to produce these graphs rather than a
                            PHP script (unless you are prepared to give PHP a couple of 100 MB of
                            allowed memory)</p>
                    </li></ol></div><p>
            </p>
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